Beam and raster locating means for thin cathode ray tube



35 mm RUUu OR 3 9379 s 9 l2 April 23, 1968 A-. SHANAFELT BEAM AND RASTERLOCATING MEANS FOR THIN CATHODE RAY TUBE Filed Oct. l9, 1965 2Sheets-Sheet 1 INVENTOR. LEO A. SHANAFELT ATTORNEY BEAM AND RASTERLOCATING MEANS FOR THIN CATHODE RAY TUBE Filed 00 19, 1965 April 23,1968- L. A. SHANAFELT 2 Sheets-Shet 2 LEO A. SHANAFElJ' BY ATTORNEYUnited States Patent 3,379,912 BEAM AND RASTER LOCATING MEANS FOR THINCATHODE RAY TUBE Leo A. Shauafeit, Woodland Hills, Calif. (416 CarnationAve., Corona Del Mar, Calif. 92625) Filed Oct. 19, 1965, Ser. No.497,850 8 Claims. (Cl. 313-76) This invention relates to a cathode raytube of the type described in Aiken Patent 2,795,731 and moreparticularly to an improvement in the electron gun structure andarrangement for guns used in such tubes, both those wherein a singlebeam is utilized and those in which more than one beam is utilized. Theimprovement is applicable to such tubes in which horizontal sweep isprovided in the conventional manner and vertical sweep is provided withan array of electrostatic deflection elements such as shown in FIGURES24 and of said patent.

Heretofore tubes in accordance with the disclosure of said patent havebeen constructed with an electron gun rigidly affixed to the tubeenvelope and with the deflection elements associated with the gunlocated within the evacuated space defined by the envelope and thehousing of the gun. For example, as shown in connection with the gundescribed in Patent 2,879,443, in particular, tubes have beenconstructed in accordance with FIGURES 24 and 25 of the first abovementioned patent with the guns being disposed within the envelope withthe deflection elements thereof also disposed within the envelope asshown in the second above mentioned patent.

Because of the criticality of the spacing and location of the deflectionelements associated with the gun it has been necessary to provide suchdeflection elements which are machined and otherwise constructed toextremely high tolerances and are located within the envelope toextremely high tolerances, the tolerance required often being no greaterthan 1:.001" in several directions. The cost of producing such tubes hasbeen very high, and the difliculty in providing a rectangular rasterwhich properly fills the screen and is properly located with respect tothe target screen in both vertical and horizontal directions has beenconsidered so severe as to make it impractical to construct a tube inwhich two images are provided by two separate guns and in whichhorizontal sweep for each of the beams is provided in the conventionalmanner and vertical deflection is provided by vertical arrays ofelectrostatic deflection elements to cause the two beams to impinge onopposite sides of a common target plate. This impracticability hasarisen because of the difliculties involved in properly positioningwithin the envelope the deflection elements which provide for horizontalsweep.

Due to the difliculty of providing a solution to this problem, all ofthe prior art which relates to positioning of guns in tubes of theaforesaid type and which contains any teaching relating to thepositioning of deflection elements with respect to'the envelope hasuniformly and unanimously disclosed placing of such deflection elementswithin the envelope as exemplified by Patents 2,879,446, 2,850,670,2,879,443, 2,795,729, 2,809,324, 2,837,691, 2,830,226, 2,928,014,2,864,033, 2,821,656, 2,978,601, 2,930,930, 2,885,595, 2,926,274 and2,896,111.

Applicant has provided as described hereinafter, a solution to theproblem of suitably locating the horizontal sweep deflection elementsand the focusing elements in such a manner that it is possible torapidly and accurately adjust them to provide for accurate properfocusing and proper registration of the raster with the screen withoutany increase in either the cost of the elements themselves or in thecost of the circuitry, while at the same time 3,379,912 Patented Apr.23, 1968 enormously reducing effort and care needed in designing andconstructing the tube.

In essence, applicant has accomplished this by providing within anextending neck portion of the envelope, only the beam generating and, ifnecessary, rough focusing elements of the gun and providing in anadjustable manner, adjacent said neck portion and outside it, thenecessary magnetic elements for controlling horizontal positions of theraster, for controlling positioning of the beam between the screen andan array of vertical deflection elements and for controlling horizontalsweep of the beam.

Thus the object of the invention which is thus attained is to providefor improved facility in controlling the position of the beam, forexample, to prevent warping of the focal plane, and to controlhorizontal adjustment of the edges of the raster and location andorientation of horizontal sweep.

The invention is described in greater detail in connection with thedrawings in which it is intended to illustrate the applicability of theinvention without thereby limiting its scope to less than that of allequivalents which will be apparent to one skilled in the art. In thedrawings like reference numerals refer to like parts and:

FIGURE 1 is a partially cross-sectional partially cutaway perspectiveview of a tube according to the invention;

FIGURE 2 is a cross-sectional perspective fragmentary view of amodification of the embodiment of FIGURE 1;

FIGURE 3 is a partially cross-sectional partially cutaway perspectiveview of another embodiment of the invention;

FIGURE 4 is a partially cross-sectional partially cutaway perspectiveview of another embodiment of the invention;

FIGURE 5 is a partially cross-sectional partially cutaway perspectiveview of another embodiment of the invention.

Referring now to FIGURE 1, there is shown a cathode ray tube indicatedgenerally as 10 comprising an envelope 11 having a projecting neckportion 12. On one interior substantially flat surface of envelope 11there is coated a suitable cathode ray tube or television tube targetscreen 13 which may be any suitable conventional phosphor material andon another substantially flat interior surface of envelope 11, parallelto and spaced from screen 13, there is provided a plurality of verticaldeflection elements 14 which may be conductive plates but each of whichis preferably provided by a coating of conductive material on aninterior surface of envelope 11. Preferably elements 14 are transparentso that the target screen 13 may be viewed from either side of tube 11.

In connection with projection 12 of envelope 11 there is provided anelectron gun indicated generally as 15 to provide electron beam 16. Gun15 preferably comprises beam-emitting element or cathode 20, heater orfilament 21 to heat cathode 20, anode 22 to control grid 23 and focusingscreen 24, all of which are located in the evacuated interior of theenvelope provided within the interior of projecting portion 12.

Exterior to projecting envelope portion 12, there is provided as anessential and critical feature of the invention, positioning magnets 25and 25 which are preferably located in the ambient atmosphere,adjustably with respect to the elements contained in the interior ofprojecting portion 12 and are preferably disposed adjacent to the outersurface of projecting portion 12. Also provided in the ambientatmosphere adjacent the exterior of portion 12 there are providedmagnetic coils 26, 26' disposed opposite each other and in a manner toprovide horizontal sweep of beam 16 with respect to target 13. Beam 16emitted by gun 15 is projected from the gun in a plane substantiallyparallel to the planes of both target 13 and elements 14 in the spacebetween target 13 and elements 14. It is caused to bend near its end andto impinge on target 13 by electrostatic force applied on elements 14 ina progressive manner to cause a lowered voltage to appear on each of theelements successively in the manner described in the patents above setforth. The manner in which said lowering of voltage is caused to appearsuccessively on elements 14 forms no part of the present invention andmay be accomplished in any of several manners set forth in the priorart.

To accomplish the objects of the invention, elements and 25 may beadjusted or moved with respect to projecting portion 12 in order tocause the sweep of beam 16 to begin and end at suitable places on targetscreen 13 and to cause the beam as it is emitted from gun 15 to liewithin a plane having the desired orientation with respect to target 13.Likewise, yoke magnets 26 and 26 may be suitably adjusted to providesuitable adjustment of the position of the beam.

Referring now to FIGURE 2, projecting portion 32 of an envelope such asenvelope 11 may be provided with a gun 35 in the same manner asindicated in connection with FIGURE 1 with the exception thatelectrostatic horizontal deflection plates 46 and 46 are provided inplace of electromagnetic deflection elements 26 and 26'. Positioningmagnets and 45 are located in the same manner as set forth above inconnection with magnets 25 and 25 and may suitably be adjusted inposition to accomplish the objects of the invention by providingsuitable horizontal adjustment of the raster and controlling position ofthe beam between the screen and the array of vertical deflectionelements.

As shown in FIGURE 3, there may be provided an envelope indicatedgenerally as 50 which may have two projecting portions 12 and 12" whichmay be provided respectively with electron guns 15 and 15". The cathoderay tube indicated generally as 15 may comprise envelope 51 havingcentral target plate 53 which may have a suitable target screen 53' and53" coated respectively on each side thereof. The vertical deflectionelements 54 and 54' are preferably provided as transparent coatings onflat interior surfaces of envelope 51 and preferably lie in planesparallel respectively to targets 53' and 53" so that beams 56 and 56emitted by guns 15' and 15 may sweep horizontally in planes parallel totargets 53' and 53". Deflection at the ends of beams into impingementwith target 53' and 53" to provide vertical sweep is provided bydeflection elements 54 and 54 in the manner described in connection withelements 14 of FIGURE 1 and successive electrostatic voltage drops maybe applied to the elements in the manner described in connection withFIGURE 1.

In the embodiment of FIGURE 3, the material of target screen 53' ispreferably of a suitable phosphor to provide for an image of one colorand the phosphor material of target 53" is preferably a phosphorselected to provide an image of a different color when struck with theelectron beam.

In a preferred embodiment of the invention, the colors are chosen suchthat a composite picture provided by the two screens, when properregistration of the two beams is provided, shows to the eye theappearance of three-color image in accordance with the theory developedby Dr. Land of Polaroid Corporation whereby a colored image registeredin the brain of a human by a human eye comprises only two colors viewedby the human eye and that realistically multi-colored image will beobserved by such brain if a suitable image having only two colorcomponents is provided on a screen which may be observed by the eye.

In FIGURES 4 and 5 there is shown the application of the invention totubes according to the invention wherein three-color and four-colorimages respectively are provided.

As shown in FIGURE 4 there may be provided a cathode ray tube indicatedgenerally as which may have an envelope 71 having projecting neckportions 12a, 12b and projecting therefrom. Electron guns 15a, 15b andwhich may be substantially identical with electron gun 15 of FIGURE 1may be provided in conjunction with said projecting portionsrespectively.

Within the interior of envelope 71, there may be provided three targetscreens 73, 73 and 73" and three arrays of vertical deflection elements74, 74' and 74", these elements preferably being all parallel to oneanother and all coated on interior portions of envelope 71 or partitionsor plates located therewithin.

Array '74 is preferably located to provide vertical sweep of beam 76 ontarget 73, array 74' to provide vertical sweep of beam '76 on target 73'and array 74" to provide vertical sweep of beam 76" on target 73", saidbeams being emitted respectively by guns 15a, 15b and 15c. Preferablyall of the elements 73, 73, 73", 74, 74' and 74" are transparent. Eachof targets 73, 73' and 73" may be of phosphors of different compositionsto provide preferably images of the three primary colors so that whenthe tube is viewed either through array 74 or array 74", the eye maycombine the images on the three target screens to receive a compositemultiple colored image provided by images on the screens when beams 76,76' and 76 are in proper registration.

It is a critical feature of the invention that in order to provide suchsuitable registration there be provided adjustable positioning magnetson the external or outside of projecting neck portions of the envelopewherein there are located other elements of the electron guns to providethe beams.

Referring now to FIGURE 5, there is shown a cathode ray tube indicatedgenerally as 90 comprising envelope 91 having projecting portions 12w,12x, 12y and 122 with which there may be associated electron guns 15w,15x, 1531 and 152 which may emit respectively beams 96, 96', 96" and96", which may impinge respectively on target screens 93, 93, 93" and93' in response to electrostatic fields provided respectively by arrays94, 9'4, 94" and 94 of vertical deflection elements. Each of such arraysand each of such target screens preferably lies in a plane and each ofsaid beams preferably sweeps horizontally in a plane and preferably allof said panes are parallel to one another but it is generally essentialto the invention that all of the arrays and all of the targets beparallel to one another. Electrostatic voltage drops are provided on thearrays in accordance with the discussion above in order to providevertical sweep of the beams on the targets respectively.

It is critical to the invention that there be provided suitableregistration of the screens and of the sweep of the beams with respectto each other in order to provide a suitable multiple colored compositeimage it suitable phosphors are provided for each of the targets. Thiscritical need is met by providing positioning magnets in accordance withthe invention. Different colored images provide a four-colored compositeimage when viewed by the eye through either array 94 or array 94". Theelements may be supported as described in connection with otherembodiments and beams are controlled in accordance with the discussionsof other embodiments above.

It may thus be seen that the invention is broad in scope and includessuch modifications as will be apparent to those skilled in the art andis to be limited only by the claims.

Having thus described my invention, I claim:

'1. In a thin cathode ray tube having a single envelope, a targetscreen, an electron gun and an array of vertical deflection plates toprovide for vertical sweep, with said gun located to produce a beamwhich sweeps in a plane parallel to and spaced apart from said screen, anecked portion of said envelope extending outwardly from said envelopeand containing therein a beam emitting cathode, at least one beamattracting anode, a beam focusing ring and a control grid, said neckedportion having adjacent the outer surface thereof a pair of positionallyadjustable magnets to control lateral location of the raster and tocontrol positioning of the beam between said screen and said array.

2. The tube of claim 1 Wherein said necked portion is also provided witha pair of electromagnets adjacent its outer surface to provide andcontrol horizontal sweep of said beam.

3. In a cathode ray tube having a single envelope and within saidenvelope two target screens and two arrays of vertical deflectionelements to provide respectively for vertical sweep of each of twoelectron beams with respect to each of said target screens, two neckedportions of said envelope extending outwardly from said envelope, theinterior of each of said necked portions communicating with the interiorof said envelope, each of said necked portions containing in itsinterior a beam emitting cathode, at least one beam attracting anode, abeam focusing ring and a control grid, whereby two beams are providedeach substantially parallel to one of said target screens and one ofsaid arrays, each of said necked portions having adjacent the outersurface thereof a pair of positionally adjustable magnets to controllateral location of the raster and to control positioning of the beambetween said screen and said array.

4. The tube of claim 3 wherein each of said necked portions is alsoprovided with a pair of electromagnets adjacent its outer surface toprovide and control horizontal sweep of the beam produced by theelements there within.

5. In a cathode ray tube having a single envelope and within saidenvelope three target screens and three arrays of vertical deflectionelements to provide respectively for vertical sweep of each of threeelectron beams with respect to each of said target screens, three neckedportions of said envelope extending outwardly from said envelope, theinterior of each of said necked portions communicating with the interiorof said envelope, each of naid necked portions containing in itsinterior a beam emitting cathode, at least one beam attracting anode, a

beam lfocusing ring and a control grid, whereby three beams are providedeach substantially parallel to one of said target screens and one ofsaid arrays, each of said necked portions having adjacent the outersurface thereof a pair of positionally adjustable magnets to controllateral location of the raster and to control positioning of the beambetween said screen and said array.

6. The tube of claim 5 where-in each of said necked portions is alsoprovided with a pair of electromagnets adjacent its outer surface toprovide and control horizontal sweep of the beam produced by theelements there within.

7. In a cathode ray tube having a single envelope and Within saidenvelope four target screens and four arrays of vertical deflectionelements to provide respectively for vertical sweep of each of :fourelectron beams with respect to each of said target screens, four neckedportions of said envelope extending outwardly from said envelope, theinterior of each of said necked portions communicating with the interiorof said envelope, each of said necked portions containing in itsinterior a beam emitting cathode, at least one beam attracting anode, abeam focusing ring and a control grid, whereby four beams are providedeach substantially parallel to one of said target screens and one ofsaid arrays, each of said necked portions having adjacent the outersurfiace thereof a pair of positionally adjustable magnets to controllateral location of the raster and to control positioning of the beambetween said screen and said array.

8. The tube of claim 7 wherein each of said necked portions is alsoprovided with a pair of electromagnets adjacent its outer surface toprovide and control horizontal sweep of the beam produced by theelements therewithin.

References Cited UNITED STATES PATENTS 2,795,729 6/1957 Gabor 315-433,299,314 1/1967 Yamada et al. 31525 JAMES W. LAWRENCE, PrimaryExaminer.

V. LAFRANCHI, Assistant Examiner.

1. IN A THIN CATHODE RAY TUBE HAVING A SINGLE ENVELOPE, A TARGET SCREEN,AN ELECTRON GUN AND AN ARRAY OF VERTICAL DEFLECTION PLATES TO PROVIDEFOR VERTICAL SWEEP, WITH SAID GUN LOCATED TO PRODUCE A BEAM WHICH SWEEPSIN A PLANE PARALLEL TO AND SPACED APART FROM SAID SCREEN, A NECKEDPORTION OF SAID ENVELOPE EXTENDING OUTWARDLY FROM SAID ENVELOPE ANDCONTAINING THEREIN A BEAM EMITTING CATHODE, AT LEAST ONE BEAM ATTRACTINGANODE, A BEAM FOCUSING RING AND A CONTROL GRID, SAID NECKED PORTIONHAVING ADJACENT THE OUTER SURFACE THEREOF A PAIR OF POSITIONALLYADJUSTABLE MAGNETS TO CONTROL LATERAL LOCATION OF THE RASTER AND TOCONTROL POSITIONING OF THE BEAM BETWEEN SAID SCREEN AND SAID ARRAY.